1. Field of the Invention
This invention relates to a calculator assembly which is mechanically operable through manipulation of certain rotatable scales comprising the assembly using the hands of the operator for the determination of chord/key calculation of musical composition.
2. Calculator assemblies used to calculate and analyze on a more specific basis chords, keys, etc. of musical composition are quite well known in the prior art. Typically, such devices are used in analyzing musical composition when a user thereof encounter chords that appear to be very complicated. Such more careful analysis is required when such complicated chords bear no relationship with the key signature in which the piece of music is composed or the rest of the composition. Many chords which are used in particular key signatures are chosen from specific major and minor chords which are related to the key signature but are frequently embellished to the point where they are no longer immediately recognizable. It is obviously desirable for a student of music to be thoroughly drilled in the major and minor chords in a particular key signature and continue work analysis through as many advanced variations of these chords as possible. It is also desirable to repeat this process using all the key signatures.
The particular chords and notes used in progressions of various kinds in music can ordinarily be selected from several chords and notes and produce substantially the same musical effect. Some arrangements however will be considerably easier to play than others. More particularly, one chord in a musical score may be played in any of its inversions or in the root position and sound somewhat the same. The difficulty in determining the next chord in the score may, and usually does, depend on the particular inversion which is used from the prior chord.
It is therefore a recognized difficulty even for experienced composers to recall all of the possible inversions of the numerous chords one may use and then to select from these inversions those which produce the most efficient sequence.
The prior art is replete with numerous calculator assemblies determining various composition, chord/key common inversions, etc. The following U.S. Patents are representative of prior art attempts to overcome certain problems as set forth above and well recognized in the prior art.
Leonard, U.S. Pat. No. 3,884,113 discloses a slide rule chord indicator having an upper dial which is rotatable to display the root tones of the related major and minor chords of any chosen key signature. The plurality of indicators are included thereon which select the particular scale tones of the related chords from named scale tones on a replaceable sheet also associated with the subject assembly.
Leonard also discloses (U.S. Pat. No. 3,884,114) an aid for teaching the related major and minor chords and requisite scale tone structure in each key signature. The apparatus comprises a rotatable dial mounted on the front panel of an envelope having a peripheral display of the scale tone names arranged according to the cycle of fourths and a plurality of movable sheets individually insertable in the envelope having an arcuate array of indicia denoting the scale tone structures of various major and minor chord types.
Further, Leonard, U.S. Pat. No. 3,908,506, discloses a device for teaching music students the correspondence between the scale tone intervals of a chord as measured with the reference of the chromatic scale and the diatonic scale. An outer rotatable disc and a concentrically and rotatably mounted inner disc are secured together wherein the inner disc has a continuous peripheral display of chord symbols of a particular chord in the various key signatures. The discs are rotatable relative to one another until the chromatic scale indicia are adjacent to a particular chord symbol on the outer disc and the subject processes are generally repeated for the diatonic scale.
Leonard also discloses in U.S. Pat. No. 4,002,097 a chord progression selector comprising a plurality of dials of increasing diameter wherein each represents a particular chord type having a peripheral array of the scale tone names of the chord in its root and inverted positions arranged in sections. Upon alignment of various sectors of the discs a given chord progression can be arranged according to the most easily played chord inversions.
While the above noted calculator assemblies are operative for their intended functions, there is still a need in this area for a more versatile and comprehensive calculator assembly which accomplishes the intended goals and functions and overcomes the prior art problems without adding undue complexity to the structure of the calculator and its process for operation.